Operators of cable communication systems have implemented a range of digital services, including digital video programming on various pay plans and broadband Internet access. Until recently, telephony was less pervasive on these systems, but is now being provided on some of these systems at an increasing rate. Cable operators have typically provided these digital services on modern hybrid fiber-coax (HFC) systems that typically provide relatively high capacity, interactive digital communication and fairly good system reliability. In these systems, however, virtually all server functions are concentrated in the cable headend.
The cable drop, from a tap to a subscriber's residence, remains a vulnerable and trouble-prone element, offering an opportunity for service improvement and maintenance cost reduction if it could be replaced with a more reliable, but still economical wireless alternative. Furthermore, there are additional service opportunities, not yet addressed, in the mobility needs of subscribers and others, including wireless delivery of entertainment services that have so far been largely confined to cables, and providing Wireless internet service provider (WISP) and micro-cellular mobile services, e.g., cellular telephony. Furthermore, reliance on an all-packet architecture may make a cable system part of the rapidly developing multimedia Internet with its, thus far, unparalleled potential for new media applications.
Outdoor WISP architectures, for example, Ricochet's relayed wireless access service in the 900 MHz band and Virginia Tech's “local neighborhood” LMDS in the 28 GHz band, are typically considered among the precedents for the concept of combining some kind of wireless drop with a wired access network. However, these systems do not address enhancements of existing cable distribution systems that may now take advantage of relatively inexpensive IEEE 802.11 wireless LAN (WLAN) technology in the unlicensed bands, provided appropriate spectral management techniques are used.
Although specific antenna architectures might be employed to create directivity between a specific access-user antenna-pair, economic considerations typically dictate that all access antennas are selected from a small set of designs and that all users' antennas are also chosen from a small set of choices. Furthermore, access antennas typically must be placed where convenient along the access line and users are usually distributed non-uniformly near the access line and at varying distances from it. All of this points to the fact that usually there will be interference between the channels serving different individual users, unless means are taken to eliminate it. Even if sub-channels of different users of the system are separated by other means of multiplexing, the need for privacy dictates the elimination of coupling between separate users' channels. The wireless channels to different users might be separated, to some extent, by using different frequency bands for different users, or by using time division or packet division multiplexing. But these methods do not use the systems capabilities efficiently and flexibly and they require relatively expensive processing equipment on the users' premises.
Of utility then are systems, apparatus and methods that allow bilateral and flexible subscriber access to an information transport system.